If time were no object, we'd all live a more secure computer life—we'd beef up our browsers, use complex passwords, and keep our data locked up with encryption Skynet couldn't crack. But that kind of stuff requires obscure software, tricky command line work, and most of a free weekend, right? Nope. Anybody can feel more secure about their systems with the help of some free software and easy tweaks and add-ons. We've rounded up a good deal of these swift and simple security fixes for Windows, Mac, and Linux, so bust out the tinfoil hats and check 'em out after the jump. Photo by ul Marga.

Lock Down Firefox

Firefox is pretty secure in its own right, but its vast library of add-ons include a number of tools that can make it even tighter. Here's a few easy-to-use ways to lock down the fox:

Vidalia (original post): The Tor anonymity network isn't a fail-proof secrecy system, or a great way to quickly transfer lots of data, but the Tor setup tool Vidalia does make it a one-installation, one-button system for anonymizing your browsing on Windows, Mac, or Linux. In short: Tor won't defeat an intrepid IT manager, but it works pretty well for most situations.

SafeHistory & SafeCache: Prevent web sites from seeing where you came from and what you were looking at before you got there with these lightweight twin extensions.

Change settings for better privacy: It's not just nosy co-workers you don't want seeing what you do online, but also any over-the shoulder hackers or snoopers who strike while you're away from the keys. Take some of Adam's advice and set Firefox to erase your private data on exit, stop keeping "address bar history," and enable a master password if you don't want to remember your legion of site logins. Here's more on locking down your autofilling web site logins with a single master password. Don't forget to set a timer to disable the Master Password accessibility if you tend to leave Firefox open when you walk away.

Always use https connections: Fans of Google's services might not know that almost every one of the search giant's tools offer a connection through SSL, the scrambled, harder-to-eavesdrop-on protocol than plain old HTTP. Can't seem to remember the "s"? Try this Greasemonkey script, which can automatically make the switch for you at pre-defined sites.

Encryption made easy

When it comes to solid, dependable encryption on a hard disk or flash drive, nothing beats TrueCrypt, now available in GUI form for Windows, Mac, and Linux, and it's not that hard to set up. Still, you don't need to set up system-wide encryption or virtual drives to ensure no nefarious third parties are looking at your communications:

If you just need to send a few documents securely to someone else, you could always compress and password-protect them with a zip utility like Lifehacker's favorite cross-platform tool 7-Zip.

For a file-by-file encryption solution in Windows, check out AxCrypt. It's still pretty beta in some ways, but the Big Bonus is adding encryption to Windows' right-click menu—doesn't get much easier than that.

Make strong but memorable passwords

The heart of any secure computer lies in its passwords—from commonly-used web passwords down to ultra-paranoid stuff like BIOS locking. If you find yourself resorting all too often to birthdays and pet names, check out the following resources:

Once you've got that uber-tight password, feel free to use it for your Windows/Mac/Linux login password or your multi-app keychain program, and then pick more basic, easy-to-grok passwords for web sites and the like, as suggested by a recent Macworld article. With the auto-suspend/lockout features in many systems, having a single, secure gateway into your data makes sense.

It won't work for every site, but getting set up with an OpenID could give you fewer passwords to keep track of and faster access to you favorite sites.

Bolt down your network

Unfortunately, there aren't a lot of shortcuts to the basics of setting up a decently secure home wireless network—setting an SSID, WPA encryption, and MAC filters are just part of the (acronym-crazy) game. Going forward, though, you can make sure the computers in your home or small office are safe without weekend-consuming projects:

We've shown you the extensive way of scanning for port security holes, but here's a much easier tool for novices— the Audit My PC online firewall test. I highly doubt it catches everything and hands out extensive troubleshooting help, but for just knowing what should and shouldn't be accessible to the outside world it is worth the price of admission.

For networking n00bs looking for a little GUI-fied help, check out the free version of Network Magic, which can help move you through the basics.

If you're not behind a router or physical/corporate firewall, be sure to turn on your operating system's firewall (not enabled by default, for instance, in OS X Leopard) and make it secure.

Lojack your laptop (and USB drives)

All the best proxies, lock-downs and passwords will only help you so much if your whole system ends up in a thief's hands. Here's how to secure, and possibly even locate, your lost goods with free tools:

iPods digital cameras and USB drives are appealing, easy-to-grab targets for thieves—believe me, I know. GadgetTheft, a free auto-run trick that you can install on any device that you can transfer a file to, will send you as much information as it can grab from a computer once you've turned on tracking. iHound, a free USB-drive-only tool, works in a similar way, but actually sends rough geo-location info based on the IP address of its captive users' computer.

A dedicated thief might not let some wailing laptop speakers stop his crime, but you can help keep coffee shop patrons honest with tools like iAlertU for the Mac and Laptop Alarm for PCs. Both can make a racket—or even snap a few incriminating pictures—if they detect something fishy going on.

Windows users have their own webcam-into-security-cam tool in Yawcam, which can even be set to send regular photos to an FTP server.

Got your own quick-but-effective security tips for n00bs or those just starting to get serious about security? We'd love to hear them in the comments.

Kevin Purdy, associate editor at Lifehacker, hopes his neighbors didn't packet-sniff an advance copy of this guide. His weekly feature, Open Sourcery, appears every Friday on Lifehacker.